Harden mail connector network boundaries

tests/test_imap_parser.py

@@ -3,11 +3,16 @@ from __future__ import annotations
 import unittest
 from unittest.mock import patch
 
+from govoplan_core.security.outbound_http import OutboundHttpBlocked
 from govoplan_mail.backend.config import ImapConfig
 from govoplan_mail.backend.sending.imap import (
+    ImapAppendError,
+    ImapConfigurationError,
     _detect_sent_folder,
     _extract_mailbox_name,
+    _fetch_message_by_uid,
     _normalize_mailbox_page,
+    _open_imap,
     _paged_descending_sequences,
     _parse_fetch_sequence,
     _select_readonly,
@@ -17,6 +22,31 @@ from govoplan_mail.backend.sending.imap import (
 
 
 class ImapFolderParserTests(unittest.TestCase):
+    def test_real_imap_connections_honor_deployment_egress_policy(self):
+        config = ImapConfig(host="imap.internal", port=993, security="tls")
+        with patch(
+            "govoplan_mail.backend.sending.imap.validate_outbound_host",
+            side_effect=OutboundHttpBlocked("private network blocked"),
+        ), self.assertRaisesRegex(ImapConfigurationError, "private network blocked"):
+            _open_imap(config)
+
+    def test_imap_revalidates_and_pins_at_connection_time(self):
+        config = ImapConfig(host="imap.example.test", port=993, security="tls")
+        public = [(2, 1, 6, "", ("93.184.216.34", 993))]
+        private = [(2, 1, 6, "", ("127.0.0.1", 993))]
+        with patch.dict(
+            "os.environ",
+            {"APP_ENV": "production", "GOVOPLAN_CONNECTOR_ALLOW_PRIVATE_NETWORKS": "false"},
+        ), patch(
+            "govoplan_core.security.outbound_http.socket.getaddrinfo",
+            side_effect=(public, private),
+        ), patch("govoplan_core.security.outbound_http.socket.socket") as socket_factory, self.assertRaisesRegex(
+            OutboundHttpBlocked,
+            "non-public network",
+        ):
+            _open_imap(config)
+        socket_factory.assert_not_called()
+
     def test_extracts_quoted_mailbox_after_quoted_delimiter(self):
         self.assertEqual(
             _extract_mailbox_name(b'(\\HasNoChildren \\Sent) "/" "Sent Items"'),
@@ -49,6 +79,23 @@ class ImapFolderParserTests(unittest.TestCase):
 
 
 class ImapMessagePaginationTests(unittest.TestCase):
+    def test_full_message_fetch_uses_partial_range_and_deployment_limit(self):
+        class Client:
+            command = ""
+
+            def uid(self, command, uid, fetch_spec):
+                del command, uid
+                self.command = fetch_spec
+                return "OK", [(b"1 (UID 1 RFC822.SIZE 11)", b"12345678901")]
+
+        client = Client()
+        with patch.dict("os.environ", {"GOVOPLAN_CONNECTOR_MAX_FILE_TRANSFER_BYTES": "10"}), self.assertRaisesRegex(
+            ImapAppendError,
+            "deployment limit",
+        ):
+            _fetch_message_by_uid(client, "1")
+        self.assertIn("BODY.PEEK[]<0.11>", client.command)
+
     def test_paginates_sequence_numbers_newest_first(self):
         self.assertEqual(
             _paged_descending_sequences(120, offset=0, limit=5),